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(No Model.) v I R. THOMPSON.

' GRATE BAR. N0.384,729. Y PatntedJune 19,'1888- :Z5 I@ n? 1/ 6? l* ir/g3 ff* v @i d f 'e 1 y/' J- Z b a Z @g2 @22M L z |f| b m 1&3 f@ f 71.5 C Z @f Zw/ZW ci@ fw -r/vn/uafv NITED STATES PATENT i OFFICE.

RICHARD THOMPSON, OF NEW YORK, ASSIGNOR OF`ONE-HALF 'IO JOHN BUSHNELL, OF BROOKLYN, NEW YORK.

enne-BAR.

' SPECIFICATION forming part of Letters raient No. 384.729, dated :une 19. 188s.

Application tiled Septembor29, 1887. Serial No. 251,015. (No model.)

To @ZZ whom it may concern.-

Beit known that I, RICHARD THOMPSON, a citizen of the United States, residing at New York, county and State of New York, have in-V vented certain new and useful Improvements in Grate-Bars,of which the following is aspeciiication.

This invention relates to that class of gratebars in which an apertured top or grating is combined with. longitudinal supporting-ribs on the under side of the same and integral therewith; and it has for its object to prevent the warping and distortion which occur in bars of this pattern as now made, because of the unequal expansion of the apertured top and longitudinal ribs. This I accomplish by transversely dividing the top or grating into sections, with sufiicient space between to allow for theirindependent expansion, and by thickening the metal of the supporting-ribs at the junctures of these sections I am enabled to thus divide the top without in any way weakening the bar; but to describe my invention more particularly I will now refer to the accompanying drawings, in which- Figure l is a plan view of my improved grate'bar. Fig. 2 is a side Velevation of the same. Fig. 3 is a transverse section cut on the line x x, Fig. 1. Fig. 4 is a transverse section cut on the line y y, Fig. 1, and Figs. 5, 6, 7, and 8 are partial plan views of modifications in the construction of the apertured top or grat-ing.

The bar is made of suitable metal, cast in one piece. The top or grating, upon the upper surface of which the fuel is placed, is composed of the cross-bars a c and `the longitudinal ties b b at the ends of the crossbars, connecting them together in sections. The number of sections into which the apertured top is to be divided will depend upon the length of. the bar. In the drawings three of these sections are shown. Sufficient space is left between the ends of the longitudinal ties b b to permit these sections to expand independ ently.

siderably thickened, as shown at d d, thus compensating for the absence of connecting ties inthe apertured top at these places and making the bar of uniform strength through its length.

As the apertured top a b of the grate-bar is in direct contact with the fuel undergoing combustion, while the longitudinal ribs c c are considerably below the same, and are kept quite cool by the circulation of air, this top attains a much higher temperature than the longitudinal ribs. In gratebars of this`pattern as now made, in which each side of the apertured top is provided with a longitudinal tie running the full length of the bar, the eX- pansion of these ties,which is considerably in excess of that of the longitudinal supporting ribs, causes warping and distortion of the bar. On thel other hand,the use of longitudinal ties integral with the apertured top greatly braces and strengthens the bar. Now, as by improved construction the bar is made fully as strong as one having a continuous top, it is evident that I obtain all the advantages of and overcome all objections to bars of this class. At the ends of the bar, in the parts generally left solid,the grooves e e are cut, thus providing for free circulation of air at these places.

The number of longitudinal ribs and the shape of the cross-ribs may be varied at pleasure without departing from my invention. In

the main views the crossbars are ring-bone pattern.

In Fig. 5 straight crossbars arranged obliquely and in Fig. 6 straight cross-bars at right angles to thelongitudinal ribs are shown.

In Fig. 7 the cross-bars are4 curved in one direction, and in Fig. 8 each cross-rib comprises two reversed curves arranged obliquely.

Having now described my invention, what I claim, and desire to secure by Letters Patent,

of the` her top transversely divided into sections,rand longitudinal supportingribs connected to the l. A gratebar consisting of an apertured` under side of said sectional topand increased in thickness or strengthened adjacent to the open spaces between the sections of the top, substantially as set forth.

2. In a grate-bar, in combination, an apertured top composed of sections, each comprising the cross-bars aV a and longitudinal Signed at New York, county and State of ties b b, and having slots e e at its ends, and New York, this 26th day of September, 1887. the longitudinal supporting-ribs c c, secured to the under side of the apertured top, and

5 having thickened parts d d adjacent to the Witnesses:

open spaces between the sections of the top, H. D. WILLIAMS, substantially as set forth. WM. H. MERsEREAU.

RICHARD THOMPSON. 

